On as-built microstructure and necessity of solution treatment in additively manufactured Inconel 939
Journal article, 2023

Increased adoption of additively manufactured superalloys has led to the consideration of revised heat treatment approaches for these materials. The rapid cooling during additive manufacturing processes has been seen to suppress gamma prime (γ′) precipitation, which has raised the possibilities for omitting the high-temperature solution treatment step that usually precedes ageing heat treatment for these alloys. In this work, the as-built microstructure of a high gamma prime fraction superalloy Inconel 939 is presented, where the absence of any γ′ precipitation is notable. However, transmission electron microscopy shows the presence of nano-sized Eta (η) phase. It is shown that the omission of solution treatment leads to the growth of the deleterious η phase upon ageing, which results in embrittlement in tensile loading. It is concluded that at least for this particular alloy the solution treatment plays a critical role in the establishment of the required microstructure and hence cannot be omitted from the heat treatment.

heat treatment

microstructure development


inconel 939

additive manufacturing


laser powder bed fusion


Abdul Shaafi Shaikh

Chalmers, Industrial and Materials Science, Materials and manufacture

Masoud Rashidi

Chalmers, Industrial and Materials Science, Materials and manufacture

Kevin Minet-Lallemand

EOS Finland Oy

Eduard Hryha

Chalmers, Industrial and Materials Science, Materials and manufacture

Powder Metallurgy

0032-5899 (ISSN) 1743-2901 (eISSN)

Vol. 66 1 3-11

Areas of Advance


Materials Science

Subject Categories

Manufacturing, Surface and Joining Technology

Metallurgy and Metallic Materials

Environmental Sciences



More information

Latest update